[CRIU] I can't dump mysqld

[Yohei Kamitsukasa]

On 7/30/16 11:50, Andrew Vagin wrote:

> On Sat, Jul 30, 2016 at 11:16:45AM +0900, Yohei Kamitsukasa wrote:
>> On 7/28/16 15:17, Andrew Vagin wrote:
>>
>>> On Thu, Jul 28, 2016 at 09:58:39AM +0900, Yohei Kamitsukasa wrote:
>>>> rt_sigaction(SIGCHLD, {0x45b940, [CHLD], SA_RESTORER|SA_RESTART|SA_SIGINFO, 0x7f6c58d163d0}, NULL, 8) = 0
>>>> ptrace(PTRACE_SETSIGMASK, 8367, 0x8, 0x7ffe72948b30) = 0
>>>> ptrace(PTRACE_SETREGSET, 8367, NT_PRSTATUS, [{0x7ffe72948b90, 216}]) = 0
>>>> ptrace(PTRACE_CONT, 8367, NULL, SIG_0)  = 0
>>>> accept(6,
>>> Could you check that all processes live in the same network namespaces?
>>>
>>> "readlink /proc/pid/ns/net" should return the same value for all
>>> processes.
>> Thank you for teaching how to check to me:)
>> I checked the network namespaces of mysqld's processes and they were in same
>> network namespace all. (A process of CRIU dumping was in the network
>> namespace.)
>>
> Could you apply the following patch [1] and try again?
> [1]: https://patchwork.criu.org/patch/1136/mbox/
>
> This patch will not fix the problem, but it will show more info about an
> error in a log file.
>
> Thanks,
> Andrew
Thank you for writing the patch.
I applied the patch and show the result.

(00.074960) Dump private signals of 1191
(00.075032) Dump private signals of 1192
(00.075103) Dump shared signals of 1093
(00.075308) Parasite syscall_ip at 0x400000
(00.076765) Set up parasite blob using memfd
(00.076806) Putting parasite blob into 0x7f0174cd9000->0x7fead3688000
(00.076866) Dumping GP/FPU registers for 1093
(00.076905) Warn  (arch/x86/crtools.c:133): Will restore 1093 with 
interrupted system call
(00.076979) xsave runtime structure
(00.077017) -----------------------
(00.077061) cwd:37f swd:0 twd:0 fop:0 mxcsr:1fa0 mxcsr_mask:ffff
(00.077101) magic1:0 extended_size:0 xstate_bv:0 xstate_size:0
(00.077139) xstate_bv: 0
(00.077176) -----------------------
(00.077215) Putting tsock into pid 1093
(00.077604) Error (parasite-syscall.c:528): Unable to connect a 
transport socket: Permission denied
(00.077693) Error (parasite-syscall.c:134): Can't block signals for 
1093: No such process
(00.077737) Error (cr-dump.c:1237): Can't infect (pid: 1093) with parasite
(00.078966) Unlock network
(00.079009) Unfreezing tasks into 1
(00.079048)     Unseizing 1093 into 1
(00.079118) Error (ptrace.c:54): Unable to detach from 1093: No such process
(00.080127) Error (cr-dump.c:1614): Dumping FAILED.

It showed 'Permission denied'. I executed the command by root user.
Is the problem related with either MySQL setting or MySQL ran by systemd?
(https://criu.org/Integration#Systemd)

Thanks,
Yohei Kamitsukasa